molasse

from The Collaborative International Dictionary of English v.0.48

Molasse \Mo*lasse"\, n. [F. molasse, prob. fr. mollasse flabby,
   flimsy, fr. L. mollis soft.] (Geol.)
   A soft Tertiary sandstone; -- applied to a rock occurring in
   Switzerland. See Chart of {Geology}.
   [1913 Webster]